Power supplies (e.g., direct current (DC) converters) are typically employed for electrical devices, such as with integrated circuit applications, to provide the desired power supply voltages. For example, FIG. 1 shows a circuit 100 illustrating a conventional DC-to-DC power supply converter 102, with input terminals 110 and output terminals 112, coupled to a load 104. Resistors 106 represent trace (e.g., lead or wire) and connector resistances (i.e., associated supply and return path resistances) between converter 102 and load 104.
As an example for low current load applications, remote sensing of a voltage level at load 104 is not required, because resistors 106 are typically less than an ohm and internal feedback resistors 108, which may be 1,000 ohms or more, maintain a desired voltage level at output terminals 112 and at load 104. However, as the current through load 104 increases, an undesired voltage drop will also increase across resistors 106, which may result in an under-voltage situation at load 104. For example, if a resistance of each resistor 106 is 0.01 ohms and a current level through load 104 is 10 amps, a voltage level at load 104 will be reduced by 0.20 volts. If the desired voltage level at load 104 is 1.2 volts, the error (0.20 volts) will exceed fifteen percent, which is generally too far out of tolerance for typical applications.
To compensate for this undesired voltage drop, remote sense paths 114 may be coupled between sense terminals 116 of converter 102 and load 104 to provide direct feedback from load 104 and allow converter 102 to actively maintain the desired voltage level at load 104 (i.e., via remote sensing). A power metal oxide semiconductor field effect transistor (MOSFET) may also be inserted between output terminal 112 (e.g., out+) of converter 102 and load 104 (i.e., the supply path) to control when load 104 receives power from converter 102. However, an on-resistance of the power MOSFET (e.g., 0.01 ohms) adds to the resistance of resistor 106 to further decrease a voltage level at load 104. Furthermore, by including the power MOSFET in the supply path, remote sensing becomes more complex and difficult.
For example, if remote sense paths 114 are connected between converter 102 and load 104 when the power MOSFET is switched off, the feedback voltage provided to converter 102 via remote sense paths 114 will be approximately zero volts and an output voltage of converter 102 may be unreliable. As an example, converter 102 may provide a maximum voltage output or a voltage output that oscillates wildly, which may result in damage to converter 102 or to surrounding circuitry. As a result, there is a need for improved power supply techniques.